• Annals of Coloproctology
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• v.34 no.6
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• pp.292-298
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• 2018

Purpose: This study compared the perioperative clinical outcomes of reduced-port laparoscopic surgery (RPLS) with those of conventional multiport laparoscopic surgery (MPLS) for patients with sigmoid colon cancer and investigated the safety and feasibility of RPLS performed by 1 surgeon and 1 camera operator. Methods: From the beginning of 2010 until the end of 2014, 605 patients underwent a colectomy for sigmoid colon cancer. We compared the characteristics, postoperative outcomes, and pathologic results for the patients who underwent RPLS and for the patients who underwent MPLS. We also compared the clinical outcomes of single-incision laparoscopic surgery (SILS) and 3-port laparoscopic surgery. Results: Of the 115 patients in the RPLS group, 59 underwent SILS and 56 underwent 3-port laparoscopic surgery. The MPLS group included 490 patients. The RPLS group had shorter operating time ($137.4{\pm}43.2minutes$ vs. $155.5{\pm}47.9minutes$, P < 0.001) and shorter incision length ($5.3{\pm}2.2cm$ vs. $7.8{\pm}1.2cm$, P < 0.001) than the MPLS group. In analyses of SILS and 3-port laparoscopic surgery, the SILS group showed younger age, longer operating time, and shorter incision length than the 3-port surgery group and exhibited a more advanced T stage, more lymphatic invasion, and larger tumor size. Conclusion: RPLS performed by 1 surgeon and 1 camera operator appears to be a feasible and safe surgical option for the treatment of patients with sigmoid colon cancer, showing comparable clinical outcomes with shorter operation time and shorter incision length than MPLS. SILS can be applied to patients with favorable tumor characteristics.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.471-479
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• 2023

In In-situ radioactivity measurement techniques, efficiency calibration models use predefined models to simulate a sample's geometry and radioactivity distribution. However, simplified efficiency calibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivity concentration results. This study aims to develop an efficiency calibration optimization methodology to improve the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulator and a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object was generated. Then, the sensitivity analysis of the efficiency calibration model was performed, and the efficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated with the designed certification value. For the sensitivity assessment of the influencing factors of the efficiency calibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size and density of the measured object. The standard deviation of the measurement efficiency as a function of the longitudinal size and density of the efficiency calibration model decreased with increasing energy region. When using the optimized efficiency calibration model, the measurement efficiency using IUE was improved compared to the measurement efficiency using ISOCS at the energy of ²²⁸Ac (911 keV) for the nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between the measured radiation concentration and the design value for each simulated subject measurement direction was 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration and the design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method, which was closer to the design value than the efficiency calibration method using ISOCS. In other words, the estimated radioactivity concentration using the optimized efficiency curve was similar to the designed radioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation, maintenance, and facility replacement of domestic byproduct generation facilities.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.710-717
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• 2008

Background: Atrial fibrillation is associated with several complications such as cerebro-vascular accidents and peripheral arterial embolism. Most of the patients who have this arrhythmia chronically feel their heart beating and so they are frightened; therefore, the quality of a patient's life is decreased. The purpose of this article is to determine the long term results of a modified Maze procedure and the factors that influence the success of the procedure. Material and Method: This study enrolled 88 patients who underwent the modified Maze with using cryoablation between June, 2001 and February, 2007. The 88 consecutive patients were divided into two groups ac cording to how the pulmonary veins were isolated, that is, with or without cryoablation. There were 58 patients who were isolated by cutting and sewing in the right pulmonary veins and by cyroablation in the left pulmonary veins in group 1 (group 1, n=58), and 30 patients who underwent isolation by cryoablation in the right & left pulmonary veins were placed in group 2 (group 2, n=30). The ECG was checked at discharge to determine the sinus conversion rate and we followed up the patients to determine whether or not the patients maintained sinus rhythm. We also checked the ECG at the last visit to determine the patients' heart rhythm. Result: The mean follow up time was $44.3{\pm}19.2$ months. At discharge, 72.4% of the patients in group 1 were in proper sinus rhythm and 66.7% of the patients in group 2 were in proper sinus rhythm. At the last follow up, 81% of the patients in group 1 were in normal sinus rhythm and 60% of the patients in group 2 were in normal sinus rhythm. When we analyzed the data via the Kaplan-Meier method, 86.5% of the patients were free from atrial fibrillation (% free from AF) at 1 year, 80% of the patients were free from atrial fibrillation at 5 year in group 1 and 70% of the patients were free from atrial fibrillation at 1 year and 51 % of the patients in group 2 were free from atrial fibrillation at 5 year. Conclusion: The modified Maze technique using cryoablation was a simple and effective procedure. But the success rate of the Maze technique using cryoblation is lower than that of the standard Maze III. The method using cryoablation shorten the operation time, but we must conduct more studies to get a better result of the modified Maze technique with using cryoablation.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.36-44
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• 2010

The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.